Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
A hospital uses an ultrasonic scanner to locate tumors in a tissue. The operating frequency of the scanner is $4.2 \mathrm{MHz}$. The speed of sound in a tissue is $1.7 \mathrm{~km} \mathrm{~s}^{-1}$. The wavelength of sound in the tissue is
PhysicsWaves and SoundCOMEDKCOMEDK 2014
Options:
  • A $4 \times 10^{-3} \mathrm{~m}$
  • B $8 \times 10^{-3} \mathrm{~m}$
  • C $4 \times 10^{-4} \mathrm{~m}$
  • D $8 \times 10^{-4} \mathrm{~m}$
Solution:
1994 Upvotes Verified Answer
The correct answer is: $4 \times 10^{-4} \mathrm{~m}$
Given, frequency, $f=4.2 \mathrm{MHz}=4.2 \times 10^{6} \mathrm{~Hz}$ Velocity of sound, $v=1.7 \mathrm{kms}^{-1}=1.7 \times 10^{3} \mathrm{~ms}^{-1}$ The wavelength of sound in the tissue is given as
$$
\begin{aligned}
\lambda &=\frac{v}{f} \quad(v=f \lambda) \\
&=\frac{1.7 \times 10^{3}}{4.2 \times 10^{6}}=4 \times 10^{-4} \mathrm{~m}
\end{aligned}
$$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.